<style type="text/css">
    .menuLoadingLayer{ display:none; position:absolute; top:0; left:0; right:0; bottom:0; background:#8d8d8d; background:rgba(0,0,0,.6);}
    .menuLoadingLayer .loading{ position:absolute; top:50%; left:50%; width:160px; height:60px; margin:-30px 0 0 -80px; text-align:center; line-height:60px; color:#fff; border:1px solid #979797; border-radius:2px; background:#cfcfcf; background:rgba(0,0,0,0.4);}
    .menuLoadingLayer .loading .fa{ font-size:16px; margin-right:4px;}
</style>
<div id="menuLoadingLayer" class="menuLoadingLayer"><div class="loading"><i class="fa fa-spinner fa-spin"></i>loading...</div></div>